Bruce Cakebread, president and COO of Napa Valley winery Cakebread Cellars, heads to a vineyard shrouded in fog during the wine harvest season in Rutherford, California September 12, 2008.

Photo: Robert Galbraith, Reuters

Bruce Cakebread, president and COO of Napa Valley winery Cakebread...

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Noto, ITALY: AFP STORY by JOE RAY : This HAND OUT PICTURE from Gulfi wines shows a carob tree stands 07 march 2007 close to the Planeta winery near the Sicilan town of Noto. Becoming a world-known grape variety such as Shiraz, Cabernet Sauvignon or Chardonnay is no mean task, yet Sicily's once little-known native red grape, Nero d'Avola, seems on the cusp of a breakthrough. AFP PHOTO (Photo credit should read -/AFP/Getty Images)

Photo: AFP, AFP/Getty Images

Noto, ITALY: AFP STORY by JOE RAY : This HAND OUT PICTURE from...

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Picked chardonnay grapes ready to be crushed at the Truchard Vineyards in the Carneros Valley.

Photo: Michael Macor, The Chronicle

Picked chardonnay grapes ready to be crushed at the Truchard...

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Morning fog rises from a vineyard north of Sonoma, Calif., April 21, 2005.

The Arctic ice cap is almost gone and glaciers are melting. European wineries are dealing with warmer temperatures, drought and changes in rain and weather patterns, yet while many California wineries are taking many steps to reduce their carbon footprint, most don't seem overly concerned about how climate changes will affect their wines.

While local wine grape growers have been buffeted from global warming by the Pacific Ocean, they've been reacting to other climate changes for years. "Climate change isn't just global warming," warns climate expert Greg Jones from Southern Oregon University. "While some areas are getting hotter, others are experiencing weather extremes and variability."

He adds: "Most (growers) in California are not doing much in terms of adaptation because the thresholds in many ways have not been met. However, if we fall into a prolonged drought, then watch the change."

In Northern California Wine Country, growers are seeing unusual and extreme weather rather than significant warming.

Current studies by Jones and Gregory B. Goodrich of the Western Kentucky University, among others, only show a 1 to 2 degree Fahrenheit average rise in temperatures in Napa Valley, mostly in nighttime temperature, not days. Some growers believe that Napa Valley might actually cool as interior valleys warm and draw cold coastal air and fog; the last few years have been unseasonably cool, in fact. Yet cumulative degree-days, a measure of overall heat accumulation, are up significantly; 585 more degree-days in St. Helena from 1930 to 2004. That increase means higher sugar - and more alcohol - and riper grapes, unless steps are taken to reduce the impact.

Mendocino might even be benefiting from changes. The Mendocino Winegrowers Alliance claims that Mendocino's Ukiah Valley has gradually cooled since the 1960s to match Napa Valley; it once was significantly hotter.

In any case, lack of local evidence doesn't mean that the industry has its head in the sand. The Napa Valley Vintners have created a task force working with Scripps Institute of Oceanography and local growers to learn how to adjust farming practices to compensate for changes.

And while many local growers say they're not doing anything different because of warming, others are changing their practices - but they say they're responding to erratic weather, not just heat. "We're not making these changes specifically to deal with climate change, but to deal with extreme weather," says Garrett Buckland, vice president of Premiere Viticultural Services in Napa.

Or as Jon Ruel, director of viticulture for Trefethen Family Vineyards, puts it: "We don't farm for average years. We're ready for whatever nature deals us." This year, that's included intense frost, rain at bloom - which damages potential grapes - and untimely heat.

Here are five ways growers and winemakers cope with new weather patterns.

Move to cooler climatesWine grape growers are increasingly planting in cooler regions, some once considered too cool for grape growing.

Many growers are edging closer to the Pacific Coast and San Francisco Bay. Carneros is now considered ideal for Merlot and Syrah once grown in warmer upper Napa Valley, while western Marin is sprouting more and more vineyards. Cooler parts of Solano and Yolo counties and even San Benito County also benefit.

All in all, however, the top destinations are Sonoma's cool coastal and mountain regions. Top wines are coming from vineyards planted just a ridge away from the frigid Pacific Ocean near Annapolis by Flowers, Premier Pacific Vineyards and Jess Jackson's Hartford Court Winery

The Napa and Sonoma microclimates produce world famous wines, but what happens if the climate changes? Local scientists and wineries are beginning to look at how to prepare.

Media: San Francisco Chronicle

Other growers and wineries have planted in the cooler parts of the Russian River Valley, where Napa's Joseph Phelps and Marimar Torres grow Pinot Noir, while other wineries in warmer areas like Dry Creek Valley have been buying property in Anderson Valley (Mendocino County). Ferrari-Carano, for instance, recently bought Lazy Creek Vineyards.

Some are heading even farther north. Humboldt County has seen an increase in grape growing. And California wineries are increasingly looking at Oregon and Washington state, including Pine Ridge in Napa, which created Archery Ridge in Oregon and more recently bought a vineyard in Washington state. Santa Cruz's Randall Grahm founded Pacific Rim winery to make Riesling in Washington state, and large Napa grape grower Premier Pacific Vineyards has bought land in Oregon and Washington state.

Some growers choose altitude for a moderate climate. Mountaintop appellations in Napa County like Howell Mountain and Atlas Peak are popular, while many vineyards have been planted at high altitudes in Lake, Sonoma and Mendocino counties, above 2,000 feet.

2. Protect grapesMore growers are managing their vineyards so that they can deal with weather extremes and erratic rainfall.

The prime consideration is grape shading. Vine orientation is the best way to shade grapes, but few growers change existing patterns unless they need to replant for other reasons.

Jim Verhey, who has a 15-acre Sauvignon Blanc vineyard just north of Napa, was fortunate that his vines were planted from northeast to southwest, close to the optimum row direction. This maximizes early and late light exposure while minimizing midday heat.

Viticulturists can also pluck fewer leaves off the vine, a practice once done to ensure ripening.

Nick Frey of the Sonoma County Winegrape Commission says canopy management is a grower's main weapon. "It begins with greater considerations of row direction and trellis types," he says."They're also removing fewer leaves on the sunny side relative to the shady side of the vine. Narrower rows also provide more shade and less heating of soil and vines."

Verhey's vines are managed by Garrett Buckland of Premiere Viticultural Services, who has largely abandoned "vertical shoot positioning," the trendy scheme of training grapevine shoots straight up for maximum sunlight. He's replaced them with a modified "lyre," a tall and narrow Y-like frame that divides the canes into two tilted sheets that partially shade the grapes while opening up the center of the rows to dappled light.

It also provides better ventilation to reduce chances of rot and mildew. These techniques come from regions like Europe where it rains during the growing season, rare until recently in California.

Other growers are experimenting with removing the first set of buds from growing vines; the later-growing buds ripen later and don't develop as much sugar.

3. Choose different grapes and wines

Winemaker and consultant Clark Smith says new clones or cultivars of more familiar varieties may be the key to continuing to grow popular grapes if the climate changes. "They can act like different varieties."

But climate expert Greg Jones' best estimate is for a 3 to 4 degree Fahrenheit increase in average temperature in prime wine-growing regions in the western United States in decades ahead. This would force many growing regions to consider planting alternate varieties. Growing practices might have to change. Traditionally, California producers managed Grenache and Carignane for high yields, producing mediocre wine. In Europe, they're often grown in demanding conditions and produce exceptional wines.

In Napa County, Chardonnay has already been retreating from the warmer upper valley to cooler Yountville and south, especially Carneros, to be replaced by more suitable - and admittedly more profitable - Cabernet.

No less than Gallo is experimenting with new cultivars at various test sites. It may have the state's largest planting of Tannat, typically found in southern France and Uruguay, at its ranch in Paso Robles. The company blends it into a wine made at Bridlewood in Santa Ynez (Santa Barbara County).

Lesser-known grapes from the Mediterranean may prove useful. Growers might plant whites from Spain and Italy like Greco di Tufo, Fiano, Falanghina and Verdejo instead of Chardonnay, notes Doug Fletcher, who heads winemaking for Terlato Wine Group. (Fletcher is the husband of Chronicle staff writer Janet Fletcher.) Likewise, he'd consider reds such as Aglianico, Negroamaro and Nero d'Avola as well as the Portuguese variety Touriga Nacional, currently grown in some warmer sites. And he notes that some Greek varieties seek to do well in hot climates, including Xinomavro. "They're interesting varieties anyway," he adds, "even if it doesn't get warmer."

Climate change is something that Mendocino County winemaker John Chiarito is very aware of as a Mendocino County farmer and winemaker. "Over the 25 years that I have been farming grapes I have noticed a shift in the seasons. The rain seems to come later and doesn't affect harvest as much anymore," he says.

In part to counter the shifts in climate, Chiarito began growing Southern Italian varietals Negroamaro and Nero d'Avola in his vineyard. "I was careful to choose ones that I was sure would continue to thrive even as the climate changed," he says. "I have developed several relationships with Sicilian producers. As part of this I got to know the wine-growing climate, which is generally warmer than here."

He finds the varietals remain balanced even in hot Sicilian weather, and is releasing his first estate-grown Nero d'Avola in November.

4. Modify winemaking techniquesUnlike changes in the vineyard, changes in winemaking can be controversial since they can involve new technologies and techniques that alarm traditionalists. These include adding oak powder during fermentation to reduce green flavors if growers are forced to pick grapes before they're fully ripe - but out of balance. Consultant Clark Smith is known for developing techniques to manipulate flawed wines, including removing excess alcohol and unwanted contamination. He notes that toasted oak powder acts like a filter. "It can remove green tannins."

If wineries opt to pick fully ripe grapes with high sugars, they may have to resort even more than today to techniques that reduce alcohol. These include high-tech reverse osmosis, spinning cone and other manipulation, or simply adding water, which is already legal and common. Other steps to make wines more like those currently popular in the market include even more acidification as well as color additives and co-fermentation with other grapes to intensify color.

Clark adds that untoasted oak chips can improve the structure of wines made from grapes that have hung too long.

5. Be smart about water use

Though heat is the most obvious threat from climate change, water may be as important long term, with droughts predicted for California. "We can bet on less water in the future," says Steve Matthiasson of Premiere Viticultural Services.

Though grape growing in dry climates allows more control of vine growth by managing irrigation, it may be difficult to find enough water. As a result, when replanting, growers are adopting more drought-tolerant rootstocks.

Almost all vineyards in California are irrigated, though some growers farm without adding water. "Dry-farming puts roots deeper," says John Williams of Frog's Leap Vineyard, one vintner who farms this way.

Left to themselves, grapevines will dig very deep for water, but irrigating causes roots to hug the surface and the water emitters. That makes them more dependent on irrigation. To counter this, Matthiasson uses two emitters per vine instead of one, and infrequent long watering to encourage roots to dig deep. Most of the vineyards he tends are irrigated, though as little as possible. "We see less dehydration in dry-farmed vineyards than irrigated ones," he says.

Lack of rain isn't the only issue. Wet weather now seems to come at inopportune times: harvest or budding. "This year, we got all our rain in three heavy events," notes Matthiasson. "Last year, it was many small rainfalls. The year before, we got damaging late rains."

Trefethen's Jon Ruel is fortunate. When Gene Trefethen planted vineyards 40 years ago, he built ponds for irrigation. He also laid drains in vineyards to remove excess water, which can be stored and used for irrigation, frost protection and cooling vines. In addition, Trefethen recycles winery wastewater.

What's happening overseas?

While we haven't seen much change in weather locally, wine-producing regions in other parts of the world have already encountered both bad and good effects from warming and changes in rainfall.

The bad effects include changes in rain patterns and drought as well as higher temperatures in Australia, Spain, southern France and Italy, such as the very hot (more than 100 degrees) heat spikes that hit all over Europe in 2003.

The good effects include frequent "California-like" vintages in Bordeaux with perfect conditions like 2005 and better ripening of grapes in cooler areas like Burgundy and the Rhine and Mosel valleys most years in the last decade, as Dr. Ernst Loosen has noted. Major European wine regions are also encountering less rain during harvest and less frost in most years.

The cool Low Countries and Scandinavia have started producing wine, and English wine is becoming viable commercially with even Champagne houses buying property for vineyards there, like Louis Roederer and Champagne Duval-Leroy looking into buying property for vineyards in Kent and Sussex. The 2006 Don's Cuvee sparkling wine from Skæresogard Vin in Jutland in Denmark won a silver medal in the 2007 Effervescents du Monde wine competition in France.